AB1403 IS MUSCLE STRENGTH ASSOCIATED WITH SPATIOTEMPORAL GAIT PARAMETERS IN PATIENTS WITH NON-SPECIFIC CHRONIC LOW BACK PAIN? THE BACKFIT PROJECT
Authors: G. Tsiarleston, Y. M. Gil-Gutiérrez, B. Donoso, E. Ruíz-Malagón, J. M. Chicano-Gutiérrez, V. Segura-Jiménez
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Non-specific chronic low back pain (NSCLBP) is one of the most common musculoskeletal disorders globally, as approximately 10-40% of individuals experience it<sup>[1]</sup>. Chronic pain is characterized when persists more than 12 weeks, and non-specific when causes of pain are of unknown origin<sup>[2]</sup>. People with NSCLBP present weakness of multifidus, transversus abdominis, internal oblique and gluteus maximus muscles and present difficulties to maintain a coherent walking due to the lack of strength and control<sup>[3]</sup>. <h3>Objectives</h3> To explore the association of back flexor, back extensor, lower- and upper-body muscle strength with spatiotemporal gait parameters in patients with NSCLBP. <h3>Methods</h3> A total of 105 patients with NSCLBP, 69 women (mean ± standard deviation= 50.9±9.9 years) participated in this cross-sectional study. Back flexor, back extensor, upper- and lower-body muscle strength were measured with reliable and valid tests (prone bridging, Biering-Sørensen, hand dynamometry (TKK 5101) and 30-second chair-stand test, respectively). Global muscle strength was calculated with normalized index (z-score) procedure from each muscle strength test. Spatiotemporal gait parameters (contact time, gait speed, stride length, stride cycle/time, double support and load respond) were obtained with an Optogait™ platform, where patients were informed to walk comfortably until 150 to 200 steps were registered in 5 meters closed circuit. Linear regression analysis was used to study the association between muscle strength and spatiotemporal gait parameters. Age, medication for pain, relaxation and depression, and fat percentage were used as covariates using the 'stepwise' method. These variables were administered via interview, except fat percentage which was measured with 8 tactile polar electrode bioimpedance system (InBody R20). <h3>Results</h3> In women, greater back flexor muscle strength was associated with lower contact time (β=-0.328), stride cycle/time (β=-0.382), double support (β=-0.313) and load respond (β=-0.302), higher gait speed (β=0.341), and longer stride length (β=0.272) (all <i>p</i>≤0.013). Greater lower-body muscle strength was associated with less contact time (β=-0.160) and double support (β=-0.237), higher gait speed (β=0.365) and longer stride length (β=0.415) (all <i>p</i>≤0.031). Greater upper-body muscle strength was associated with higher gait speed (β=0.380) and longer stride length (β=0.476) (all <i>p</i>≤0.001). Greater global muscle strength was associated with less contact time (β=-0.370), stride cycle/time (β=-0.468), double support (β= -0.324) and lower load respond (β=-0.320), higher gait speed (β=0.431) and longer stride length (β=0.491) (all <i>p</i>≤0.03). In men, greater back extensor muscle strength was associated with higher gait speed (β=0.353), and lower double support (β=-0.387) and load respond (β=-0.365) (all <i>p</i>≤0.038). Greater lower-body muscle strength was associated with lower stride cycle/time (β=-0.342) (<i>p</i>=0.044). Greater global muscle strength was associated with higher gait speed (β= 0.414), longer stride length (β=0.410), and lower double support (β=-0.373) and load respond (β=-0.354) (all <i>p</i>≤0.037). <h3>Conclusion</h3> Our findings suggest that greater muscle strength was consistently associated with better spatiotemporal gait parameters in females and males patients with NSCLBP. Future studies might determine whether randomized control trial focused on strengthening global musculature might contribute to improve gait abnormalities in patients with NSCLBP. <h3>References</h3> [1]O'Sullivan, P. Manual Therapy, 2005; 10(4): 242–255. [2]McGill, S. Back Mechanic. (2015). [3]Kim, B., et al The Tohoku Journal of Experimental Medicine, 2020; 251(3): 193–20 <h3>Acknowledgements</h3> The authors thank all the researcher involved in the fieldwork. Participants are deeply acknowledged for their collaboration and great enthusiasm during the development of the study. This study was supported by the Instituto de Salud Carlos III through the reserch contract Miguel Servet (CP20/00178) co-funded by European Social Fund. Furthermore, BD-P was supported by the "Margarita Salas" postdoctoral grant UCOR01MS. <h3>Disclosure of Interests</h3> None Declared.